Action: Use different planting or seeding methods
- Four studies (including one replicated, randomized study) in Australia, Brazil, Costa Rica and Mexico found no effect of planting or seeding methods on the size and survival rate of seedlings.
- One replicated, controlled study in Brazil found that planting early succession pioneer tree species decreased the height of other planted species.
Different planting methods have been developed to improve the establishment of the planted trees.
Supporting evidence from individual studies
A replicated study in tropical forest in Mexico (Negreros-Castillo & Hall 1996) found that seeding method had no effect on mahogany Swietenia macrophylla seedling survival and height. Survival rate (32-35%) and height (20-22 cm) did not differ between treatments. Twenty-five plots (0.2 ha) were each seeded with 300 mahogany seeds using two seeding methods: seeds dropped from 1 m height and seeds planted into 3 cm deep holes. Data were collected 12 months after seeding.
A replicated, controlled study in 2001-2002 in eucalypt forest in Australia (Parsons et al. 2006) found no effect of planting density on planted seedlings biomass and survival rate. Seedling weight (low density 34.2; high density: 34.5 g dry mass/plot) and survival (leaving plant/18 plants) (low density 11.3; high density: 11.4) were similar between treatments. Data were collected in winter 2002 in 16 replicates (each planted with a different species) of eight plots: four planted at low-density (with nine plants) and four at high-density (0.5 and 0.1 m between plants respectively) in August 2001, at each of two rehabilitated bauxite-mine sites.
A replicated, randomized study in 2004-2005 in tropical forest in Paraná, Brazil (Bruel, Marques & Britez 2010) found no difference between manual or mechanical planting on seedlings growth rate. One year after planting, the height (manual: 88 cm; mechanical: 59 cm) and height relative growth (manual: 0.88 cm/cm; mechanical: 0.98 cm/cm) were similar between treatments. Two treatments: manual planting (holes dug manually; seedlings wrapped in polyethylene bags) and mechanical planting (soil prepared with a rotary tiller attached to a tractor; seedlings in polypropylene tubes) were established in three random 20 × 20 m plots. Seedlings were planted in July 2004 and were measured one month and 13 months after planting.
A replicated, paired-sites study in 2004-2008 in tropical forest in Costa Rica (Holl et al. 2011) found no effect of planting method on seedling survival, height, and canopy area. For the four planted species, there was no difference between patch and plantation treatments for: survival (Terminalia amazonia: 70-75%; Vochysia guatemalensis: 74-77%; Erythrina poeppigiana: 84-87%; Inga edulis: 95-97%), height increase (T. amazonia: 1.8-2.3 m; V. guatemalensis: 2.5-3.0 m; E. poeppigiana: 3.7-3.9 m; I. edulis: 4.2-4.8 m) and canopy area (T. amazonia: 2-4 m2; V. guatemalensis: 5-7 m2; E. poeppigiana: 7-8 m2; I. edulis: 25-30 m2). Twelve pairs of two treatments (50 × 50 m): patch (two small, two medium, and two large patches each planted with 5, 13 and 25 seedlings of the four species respectively) and plantation (313 seedlings of the four species planted throughout) were established in 2004-2005. Data were collected three years after planting.
A replicated, controlled study in 2004-2008 in tropical forest in Brazil (Massad et al. 2011) found that planting early succession pioneer tree species decreased the height of the other planted species. Seedlings were taller in plots without pioneer species (no pioneers planted: 269 cm; pioneers planted: 243 cm). In 2004, thirty six plots (50 × 50 m) were planted with 4–9 tree-seedlings/m2. Half of the plots were planted with seedlings of 120 non-pioneer tree species and half of the plots were also planted with 2-4 pioneer species. Data were collected in 2008. All plots were cleared and then abandoned in 1990.
- Negreros-Castillo P. & Hall R.B. (1996) First-year results of partial overstory removal and direct seeding of mahogany (Swietenia macrophylla) in Quintana Roo, Mexico. Journal of Sustainable Forestry, 3, 65-76
- Parsons M.H., Koch J., Lamont B.B., Vlahos S. & Fairbanks M.M. (2006) Planting density effects and selective herbivory by kangaroos on species used in restoring forest communities. Forest ecology and management, 229, 39-49
- Bruel B.O., Marques M. & Britez R.M. (2010) Survival and growth of tree species under two direct seedling planting systems. Restoration Ecology, 18, 414-417
- Holl K.D., Zahawi R.A., Cole R.J., Ostertag R. & Cordell S. (2011) Planting Seedlings in Tree Islands Versus Plantations as a Large‐Scale Tropical Forest Restoration Strategy. Restoration Ecology, 19, 470-479
- Massad T.J., Chambers J.Q., Rolim S.G., Jesus R.M. & Dyer L.A. (2011) Restoration of pasture to forest in Brazil's Mata Atlantica: the roles of herbivory, seedling defenses, and plot design in reforestation. Restoration Ecology, 19, 257-267